What numbers multiply to -56 and adds up to 1?

Answer 1

-55

Answer 2

8 & -7 (see below)

1. x * y = -56

2. x + y = 1

We can rewrite 2. as y = -x + 1

We can then substitute this into 1. to give:

x (-x + 1) = -56

-x2 + x = -56

-x2 + x + 56 = 0

This factors to:

(-x + 8) (x + 7) = 0

Therefore:

-x + 8 = 0

x = 8

and

x + 7 = 0

x = -7

Therefore the two numbers are 8 & -7.